Electromagnet control apparatus

ABSTRACT

A control for operating a fluid actuated device includes an electrically actuated pilot valve for controlling flow of pressurized fluid to the device. The pilot valve has an electromagnet for actuating the valve against a high resistance to being initially opened and a much lower resistance to being maintained in the open state. An electrical control circuit initially introduces a high potential to the electromagnet to open the valve and subsequently introduces a low potential to the electromagnet to maintain the valve in the open state, whereby the fluid activated device is maintained in the actuated state with significantly less power than that used to initially actuate the device.

[75] Inventor:

[73] Assignee: vetco Offshore Industries, Inc.,

Baugh 1 41 ELEcTRoMAGNET CONTROL 9 APPARATUS Benton F. Baugh, Houston,Tex.

7 Ventura, Calif..

[221 Filed: Sept, 28, 1972' I 21 Appl. No.2 293,007

.52 u.s.'c1' 251/129, 317/154, 317/010. 4

f 1451 Dec. 17, 1974 Primary Examiner-Arnold Rosenthal Attorney, Agent,-or Firm-Bernard Kriegel [57] v v I 7 ABSTRACT A control for operating afluid actuated device includes an"electricallyactuated pilot'valve forcontrolling flow of pressurized fluidto the' device. The pilot valve hasan electromagn'et for actuating" the valve against a high resistance tobeing initially opened and- 3 a much lower resistance tobeing maintainedin the open-state. An electrical control circuit initially introduces ahigh potential -to the electromagnet'to' open the valve andsubsequentlyintroduces a low potential to the electromagnet to maintainthe valve in the open that used to initially actuate the device.

7 Claims, 7 Drawing" Figures 51 1111.01 H0lh 47/04,*1=161 31/06 {58],Field of Search 251/129, 141, 68; 317/154,

' '3l7/DIG.4

I [56] References Cited UNITED STATES. PATENTS 3,371,252 2/1968 James..3l-7/DlG.4. 3,469,818 9/1969 Cowan 251 129 FOREIGN PATENTS QRAPPLICATIONS 1,028,845 4/1958 Germany 251/129 PAIENIED m1 H914 3.854.695SHEET 10F 4 sum 2 or 4 mum-10mm 1 m4 I I w w Em mm w QM ,m KM s Mm v mwa QM NR. /A\ k v, MN wmw m \m\ R MM R Q MW Mu, WW. RM. WWW

PAIENIEU mac: 7 am saw u or 4 ELECTR'OMAGNET Omani-mus The-presentinvention relates generallyto controls.

for reducing the'power consumption of-an electromagnetand morespecifically to electrically operated-de- I vices fordetermining-theflow of fluid to-a fluidactuated device. I Whena wellisdrilled in relatively deep water,.as.

from an ocean floor, it is often desirableto .drill and v complete thewell at the-ocean floor with-devices which can'be remotely controlledfrom a location above the' surface of thewater. A plurality of thesedevices, which may include blowout preventers, hydraulic connectors,

and valves,'may be employed in controlling different functions on asingle -well. Usually'these devices are re motely operated by apressurized fluid which is con-- pilot valves. When 'asolenoid isenergized,'thefpilot valve is openedja'nd thepressurized fluid isdirected to the device. t v

In the past, apparatus for controlling the energizing ofthe solenoid orelectromagnet in each of the pilot valves has included a source ofrelatively high operating potential and a switch for' selectivelyintroducing the high potentialto the electromagnet. Thus, by oper--ation of the switc'h,'the electromagnet has been-ener g'iz'ed to'openor' otherwise' activate-the valve and acti vate the deviceltis oftennecessary to activate the devices for an extended period of time. Undersuch circumstances, the

high potential introduced to each 'solenoid is' continued 'inmaintaining the pilot-valve in its-actuated or open state. However, atthe" relatively high energizing potential,.each pilot valve previouslyused has consumed as trolled byappropria'te actuation of'solenoid'actuated' much as 360 watts' of power. The generation ofelectric power at the offshore location of a subsea well is expensive,the high power consumption of eachvalve being v correspondingly costly.This problem has been compounded bythe' multiplicity of pilot valveswhich may be provided ateach well. For example, a typical instal lationincluding seven pilot valves has previouslyconsumed about 2,500 watts ofpower. In order to carry.

this amount of electricity to the remote locations, such as the oceanfloor, large expensive transmission lines arerequired.

The high power consumption has also been critical energized over anextended period of time, the solenoids or electromagnets haveoverheated, resulting in with respect to the reliability of the pilotvalves.' When their unreliability and failure. Failure of a pilot valveobviously requires its replacement at great cost.

In the present invention, a pilot valve includes an electromagnet havinga coil and a plunger or armature initially biased to an extended or oneposition when the coil is deenergized, and drawn to another or proximateposition when the mills energized. This movement of n the plunger opensor otherwise operates a valve connected to the plunger, controlling theflow of a pressurized fluid that actuatesa device.

A relatively large-force must-be used to intially' overcome the bias onthe plunger, However, once the plunger is in its proximate position, aforce of signifi cantly less magnitude can be relied upon to maintainthis disposition. For example, when the plunger is in the extendedposition, about 360 watts may be required to move the plunger to theproximate position; however,

the plunger can be maintained "in the: proximate, positioniwith onlyabout two-watts of power.

Inone example of the? invention, acontrol apparatus is-providedwith afirst source ofrel ativelyi low operating potential'and a second source(if-relatively high o'pera't-ing potential. A .flrst relay-,-havingfirstand second sets of vcontacts,.and.a second-relay, havingthird and fourth sets of contacts,'are alsoprovided. The. second sourceof operating potential is'introduced through the fourth set of contactsto'th'e coilof-the electromagnet.

' The first potential is introduced through the second and third-sets ofcontacts to the coil .in the electromag net. A-coil in each of the firstand second relays is connected through a first switch to the firstsource of operating potential. 'Additionally,'the coil in' the firstrelay is connected through the'first contacts and'a' second v switch'tothe first-source. of operating potential. Except forlthe secondswitch'and-"the third-ContactsQeach of the contacts and switches isnormally open. v When the first switehis closed, thefirst'and secondrelays are activated "so that the high potential; is

will be-deactivatedso thatth'e low-potential is introducedto'theelectromag'net. This low potential can 3O v shifted by the plungerin moivingtoitsproximate position, until-the second switch isopenedandthe plunger maintain the pilot valve the state to which it has beenis returned orbia'sed to. its extended position;

These features of the control apparatusv are of signifi- Icantadvantage, especially where electromagnets and solenoids .must beactuated at remote locationsifrom the control apparatus. Whereas sevenof the devices of theprior art, for example, mightconsumeasmuch as about2,500 watts, the device of the present invention would consume only.about as much power as a 15 watt light bulb. Not only. is the cost ofthe electricity consumed lower, but the size of-the transmission linescan I be substantially decreased. Furthermore, ;the. pilot valves willnot overheat making them considerably more reliable over extendedperiods than the devices of the prior art." v v This invention possessesmanyother advantages, and

has other purposes'which may be made more clearly apparent from aconsideration of a form in which it, may be embodied. This form is shownin the drawings accompanying and forming part of the present specifi-.

cation. It will'now be described in detail, for the-pun pose ofillustrating the general principles of the invention; but it is to beunderstood that such detailed description is not to be taken in alimited sense.

Referring to the drawings:

? FIG, 1 is a side elevation 'view'of a completioncon trol pod-includinga control valve and a determining its operation; v

FIG. 2 is a longitudinal cross-section of the pilot valve illustrated inFIG. 1;

pilot valvefor FIG. 3 is a longitudinal cross-section of the controlvalve illustrated in FIGII; I t

FIG. 415a schematic view of a control circuit for electricallyactuatingthe pilot valve, wherein the controlcircuit is disposed in afirst mode of operation;

'tion; and

FIG. 5 is a schematic view of the control circuit illustrated in FIG. 4and disposed in a second mode of operation;

FIG. 6 is a schematic view of the control circuit illustrated in FIG. 4and disposed in a third mode of opera- FIG. 7 is a schematic view of thecontrol circuit illustrated in FIG. 4 and disposed in a fourth mode ofoperation.

To satisfactorily complete a well on the floor of the ocean, numerousfluid actuated devices, such as flowout preventers, hydraulicconnectors, and valves are employed. Onesuch fluid actuated device 11 isillustrated schematically in FIG. 1. A completion control I pod 13 isadapted to have a high pressure fluid line as- A pilot valve 21 isconnected to the signal wires 17 I and communicates with the supply hose19, providing ameans for controlling fluid flow to the fluid actuateddevice 11. This pilot valve controls the flow of fluid to a controlvalve31, that, in turn, controls the flow of the fluid passing through thelines 15, 19 to the device 11.

Actually, a plurality of sets of apilot valve 21, control valve 31 andfluid actuated device 11 are disposed at the ocean floor to controldifferentfunctions relating to the well extending downwardly from theocean floor. However, for simplicity of illustration, only a single setof pilot valve, control valve and fluid actuated device is illustratedin the drawings. I

The control pod l3includes a mainbody 12 having a passage 14therethrough connected to the supply hose 19 for conducting fluid underpressure to an inlet or supply of the pilot valve 21. This portcommunicates with. an inlet passage 25a in an outer body 25b thatcommunicates with a passage 67 in a pusher 67a disposed within a radialopening 67b in an inner valve body 25c, this pusher member bearingagainst a radial shear seal 25d extending inwardly of the body 250 andadapted to bear against the upstream side of 59a of a gate valve 59movable longitudinally in the inner body. The pusher member is adaptedto be acted upon by the fluid'pressure in the inlet passage 25a to beurged inwardly and to be retained in sealed relation against the sealelement 25d, in turn holding such seal element 59a of the gate valvebearing against the upstream face member.

As disclosed in FIG. 2, the pilot valve 21 is in a closed position, inthat a lateral passage 61 extending through the gate 59 is out ofalignment with the shear seal 25d. The gate valve is located in theclosed upper position, illustrated inFIG. 2, by engagement of anupwardly extending shoulder 59b thereon against a companion to the outerbody member 25b, as by means of screws 201. The 'gate'valve member 59 isshiftableto an open condition, as described hereinbelow', to bring alower stop shoulder 202 thereon against a companion lower shoulder 203on the inner valve body 25c, which effects alignment ofthe transversepassage 61 through the gate valve member with the inlet shear seal 25dand also with an outlet shear seal element 204 bearing "against thedownstream side 205 of the gate valve member, the element 204 engagingaradially disposed 'pusher mem-- ber 206 mounted within the valve body25c, the fluid flowing through the shear seal 204 and the pusher member206 into an outlet passage 29a communicating with an outlet port 29that, in turn, communicates with an outlet passage 29b extending to aninlet port 39 of the control valve 31. i

When the gate valve member 59. is in its upper or closed position (FIG.2), the fluid in the outlet passage 29a can exhaust through thedownstream pusher member 206 and shear seal 204 into an exhaust passage63 provided in the gate valve member, this exhaust pas-- sage openinginto an outlet passage 27a in the valve body 25c extending to an exhaustport member27 that communicates with a suitable exhaust line (not shown)that may extend to any suitable location, as to the vessel or drillingplatform at the surface of the water.

To facilitate shifting of the gate valve member 59, which is a flat,plate-like member, between its closed and opened positions, itsdownstream face 205 bears v against spaced rollers 65 suitably rotatablymounted in the valve body 250, as through the aid of needle bearbeingslidable within a companion bore 221 in the inner valve body 25c.Similarly, the upper portion 222 of the valve member is cylindrical,being slidable through a companion axial bore 223 in the adapter 200,this upper cylindrical portion being suitably secured to a I I valveoperating stem69, as by means of transverse pins 229. The outer stem isdisposed within an'electrornagnetic or solenoid assembly 41suitablysecured to the adapter 200. I

The solenoid assemblyincludes-anouter magnetic core 51 secured to aninner magnetic core 52 by radial "screws 53 bearingv against a taperedface 54fon the .lower flange 55 of the inner core, which bears against adownwardly facing shoulder 55a in the outer core 51.

I Between the inner and outer cores is disposed the coil 47 of theelectromagnetic or solenoid, the windings of which are connected to thesignal wires 17, that may extend through the hose assembly 15 to theoperating shoulder 590 on an adapter plate 200 suitably secured locationon the drilling vessel or platform at the top-of the water. The pilotvalve 21 is initially urged tothe closed position, illustrated in FIG.2, by a helical compression spring 57, the lower end of which bearsagainst a shoulder 56 on the inner core 52 and the upper end of whichbears against a magnetic plunger 53a threadedly or otherwise suitablyattached to the upper end of thestem 69 and locked thereto by. asuitable lock nut 240 threaded on the stem. When the circuit to thesolenoid'4l is open, the spring 57 pushes the valve stem 69 and 'theplunger 53a to an extendedposition, the inner tapered end 241 of theplunger being spaced from the companion tapered end 242 of the innercore 52 by a predetermined distance, providing a gap 55a therebetween. Asleeve 243 is clamped between the upper end of the outer core 51 and anupwardly facing shoulder r 244 on the inner core 52, the periphery 245of the. *plunger 'or'armature 5311 having a suitable clearance withrespect to su'ch"sleeve.' v

'When the circuit'to' the solenoid coil 47 is completed, the plunger-53ais'attracted iriwa'rdly'to shift the gate valve member 59 to the openposition in which its lat-- eralpassage 61 is in alignment with theshear plugs d,

1 204; This position is determined bythe engagement of thelower stopshoulder 202 with'the companion sho'ul der 203 in the inner valve body250. At this time, the

gap 55a between the plunger 53a and the inner core 52 has been reducedconsiderably. By way of example, the

, spring 57 to shift the pilot valve to its initialposition in gap 55a,priorto the energizing of theelectromagnet,

may be about 0.200 inches; whereas, the gap 55a, with the electromagnetenergized, may be about 0.030

inchesL-Thus, in thespecific pilot valve'21 disclosed, it is initiallydisposed in a closed position when the electromagnet isdeenergized,and'is shifted to the open position and retained in such open positionwhen the electromagnet is energized. I i

, The control valve 31 includes a ing an actuating port member 301communicating with the outleto'r discharge passage 29a, 29b of the pilotvalve, anoutletport member 302 communicating with the passage'37a in thepod body 12 that leads to the fluid activated device 11,, a supply portmember 303 va ve body 300 hav} communicating withthe source of fluidpressure flow- 1 ing through the passage, 14in the body from the'highpressure hose '19, and an exhaust port member 304 communicating with anexhaust passage (not shown) that may extend to a suitable exhaust line(not shown).

A shiftable valve member 305 is. movable within the f valve body 300,this valve member extending across the exhaust, outlet and inlet portmembers 304, 302, 303.

As disclosed, the inlet 303 is' closed, but-the; passage cates throughapassage'310, 310a, 3l0b in the shiftable valve member with the exhaustport member 304,- as illustrated inFlG. 3. The valve member 305is'shifted and'retained in this position by a helical compression spring311 disposed within-the valve body housing ex- .te'nsion300a, the outerportion of the spring bearing against an end wall 312 of the housing,and the inner portion'of the spring bearing against a head 313threadedly or otherwise suitablysecured to the movable valve member 305,shiftingv a shoulder 314 on this valve 37a leading tothe fluid activateddevice 11 communimember into engagement with a companion stop shoulder3l5.in the valve body 300. At this-time, the passage 37a leading to andfrom the fluid activated device 11 is in an exhaust condition, in whichno fluid pressure is suppliedto'the device 11. When the electromagnetcoil 47 is energized to pill the plunger 53a inwardly, which actsthrough the valve stem 69 to shift the gage-member 59 to the valveopening position, at which its transverse passage '61 is aligned withthe shear seals 25d, 204, fluid under pressure. flows through the line29a, 29b and through the seal sub 301 that communicates with the headend 320 I of a cylinder 321 containing thepiston portion 322 oftheshiftable valve member 305. The fluid under pressure shifts the valvemember305, as to the right illustrated in FIG. 3, to place the port31011 in communication with the inlet po'rt303 and the other port '310bin. communication with the outlet port 302 of the control valve 31. Thisposition is determined by engagement of a shoulde'r325 on the valvemember 305 with a com- .l0wer operating potentials.

panion shoulder 326 on the closure portion 327 of the Acontrol'valve'body. Fluid under pressure Jc'an then flow from'the supplyhose 19 to the inletport 303, and then through the valve memberpassages310a, 310,310b,to the-outletport302, and then through the body passage37a-to the fluid activated device 11. The deenergizing A of the solenoidor electromagnet 41 will cause the which the fluid passage 2%, 29acommunicates through the exhaust path 63 in thegatev'alve '59 to the 1exhaust line 27a,there by.relieving the fluid1.pressure in the cylinder.321," which willthen permit the control valve spring 3ll.to shift thevalvemember 305'back toits initial position,.in which the fluid line37dleading-to the fluid activated device 1 1 communicates through the path302, 310a, 310, 31017 to the exhaust port member 304 and the exhaustline.

In both the pilot valve and the control valve,suitable seal rings areprovided to prevent fluid'leakage between the several parts, as shown.-

' The -present invention involves plunger 53a can be maintained initsproxirnate position with'less power than that used told'rawtheplunger-53a from its extended position to its proximate position.

This can be'generally explained with reference to the dimensions of thegap a; When the gap 55a is relaremain activated for an extended periodof time. This not only will reduce the consumption of power, but alsothe'heatbuildup-within the pilot valve 21, A

An electrical circuit71 providing these advantages is illustratedschematically in FlGS. 4 through'7. Generally, the electrical circuit 71includes first and second' sources of operating potential73 and 75,respectively. The ,first'source 73v provides'a relatively low potential,

such as 24 volts, while the second source 75 preferably providesa'relatively high potential, such as volts.

Switching means, shown generally at 77, is connected "to the sources ofpotential 73 and 75 to selectively energize the pilot valve 21 withone'of the higher and The switching means 77 can include a first relay79 having a coil 81 and first and second sets of contacts 83; and 85,respectively. A second relay 87 can be similarly provided with a coil-89"and third and fourth sets of contacts 91 and 93, respectively. Thefirst, second and fourth contacts, 83, 85 and v93, respectively,normally provide an open circuit while thethird set of contacts 91normally provides a closed circuit.

' A normally open switch-95 is connected between the first source 73 andthe coils 81'and 89 to selectivelyenergize the first and second relays79' and 87, respectively, with the lower potential. The coil 81isalsoconnectedto one of the first contacts 83. The other of the firstcontacts 83 is connected through a normally closed switch 97 to thefirst source of operating potential 73. I

the fact that the A conductor 99 provides continuity between the firstsource 73 and one of the second contacts 85. Similarly, a conductor 101provides continuity between the other of the second contacts 85 and oneof the third contacts 91. The other of the third contacts 91 isconnected through the signal wire 17 to the connector 45. A thirdconductor 103 is connected between the source of operating potential 75and one of the fourth contacts while the other of the fourth contacts 93is connected through the signal wire 17 to the connector 45. Thenormally open switch 95 and the normally closed switch 97 are preferablypush button switches which are biased to provide their normalcharacteristics.

The structural features set forth above provide the switching means 77with at least four modes of operation. A first mode of operation,wherein the coil 47 of the pilot valve 21 is deenergized, is illustratedin FIG.

4. With each of the contacts 83, 85, 9 1 and 93, and

each of the switches 95 and 97 disposed-in their normal states, aspreviously described and illustrated-in FIG. 4,

the coil 47- is deenergized so that the pilot valve 21 and control valve31 are in their exhaust conditions, the device 11 being deactivated. g I

When the push-button switch 95 is closed, the first and second relays,79 and 87 are energized. In this second mode of operation, illustratedin FIG. 5, the first, second and fourth contacts 83, 85, 93 provideclosed circuits, whilethe' third contacts 91 provide an open circuit.This-enables the source of higher operating po- I pressure to flowintothe control valve member 305 to its open condition in which fluid underpressure can flow from'the pressure line 19 through the inlet and outletpassages 14, 37a to the device 1 1, to actuate the latter.

It will also be noted that theenergizing of the relay 8 button switch97' is released; it returns to its normally closed state, and thecircuit 71 returns to its first mode of operation (FIG. 4).

The switches 95 and 97 can be disposed on an operating panel (not shown)to provide the simplest of operating procedures whereinthe push buttonswitch 95 I tion and thereby causethe device 11 to be actuated, thehigher operating potential 75 is'introduced to the coil 47. Continuedenergizing of the coil 47 with the- -high operating potential 75 wouldretain the plunger I 53a in the proximate position, but it might alsoresult in overheating of the pilot valve 21. I-Iowever,-as soon as theplunger 53 moves to the proximate position and the push button switch95is released; the electrical circuit 71 automatically switches thelowe'r. potential 73 to the coil 47 to maintain the plunger 53a'initslproximate position. The lower potential decreases the amount ofcurrent drawn by the electromagnet assembly 41 and significantly reducesthe'power-'consumption of the pilot valve 21. Inv the examplegive'nabove, the power consumption is reducedseveral-times, as from 320' wattsin a singlepilot valve to'about -2 watts. With arevduced current inthecoil 47,,there' isno danger of failure due to overheating. Theeffective life of the pilot 'valve .21 is substantially increased alongwith its reli-' ability.

The reduced current is it is realized that-the signal wires 17 whichcarry the current can be reduced insize. This is of' paramount 79completes a-circuit through the firstz contact 83 so that the coil 81 isalso energized by the lower operating potential 73;through thesecond'switch 97. This alternate path for energizing the coil81 givesrise'to'the third mode of operation illustrated in FIG. 6. As'soon aspressure is relieved from the push button switch 95 and i-t returns toits normally open position, the second relay 87 is deenergized. and thethird and fourth contacts 91 and 93 return to their normally closed andnormally open states, respectively. However, the first relay v79 remainsenergized through the switch 97 and the first contacts 83 so that thesecond contacts 85 continue to provide a closed circuit. The lowerpotential from the source 73 is then introduced through the conthird andfourth contacts 91, 93 remaining in their closed and open states,respectively. When the push significance when the electricity istransmitted to a re mote location such as the floor of the ocean.

Iclaim: v 1. In apparatus for effecting operation of a fluid actuateddevice: valve means operatively; connectableto a source of fluidpressure and to the device, said valve means including a valve'member'shiftable between a first position preventing flow of fluid fromthe source to the device and a' second position permitting flow of fluidfrom thesource to the device;'an electrically actutrically actuatedmeans to effect shifting of said valve member from said one position tosaid other position;

and means for supplying electric power to said electrically actuatedmeans of a second particular value substantially less than said firstvalue toretain saidvalve means in said other position; said electricpower of a first value comprising a first source providing a relativelyhigh potential; said electric power of a second value comprising asecond source providing a relatively lower potential than said highpotential; switching meansfor selectively connecting said first sourceof a: high potential to said electrically actuated means to.

' means comprises a first relay selectively 'energ izable by especiallyappreciated when i the lower potential to introduce the higher potentialto a the electrically actuated-means, asecond relay connected tothefirst relayand energizable to introduce the lower potential to theelectrically actuated means,

' a first normally open switch connect'edto the source of lowerpotential'and operable to simultaneously energize the first and'secondrelays so that the lower potential is introduced to the second relay andthe high po ated device: valve means operatively connectable to a sourceof fluid pressure and to the device said valve means including a valvemember shiftable between a first position preventing flow of fluid fromthe source to the deviceand'a second position'permitting flow of fluidfrom the source to the device; an electrically actuated meansoperativelyconnected to said valve member for shifting said valve member fromon'eof said positions to the other of said positions; means forsupplying electric power of afirst particular value to said electricallyactuated means to effectshifting of said valve memberfrom said oneposition to said other position; and means for supplying electric powerto said electrically actuated means of a second particular valuesubstantiallyless than said first value to retain said valve means insaid other position; wherein said one of said positions is said firstposition and said'other of said pocloser to said electromagnet; meansfor supplying elecshifting of said plunger from extended position toproxv sitions issaid second position; said electric power of afirst'valu'e comprising a first source providing a relatively highpotential; said electric power of a second value comprising a secondsource providing a relatively lower potential 'than said high potential;switching means for selectively connecting said firstsource of higherpotential to said electrically actuated means-to shift said valvememberto said second position or for connecting said second source of lowerpotential to said electrically actuatedmeans to retain said valve memberin said second position; wherein said switching v means comprises'afirst'relay selectively energizable by the lower potential to introducethe higher potential to the electrically actuated means, a second'relayconnected to the first relay and energizable'to introduce the lowerpotential to the electrically actuated means,

a first normally open switch connected to the source of lower potentialand operable to simultaneously energize the first and second relaysso'that the lower potensitions to the other of said positions,saidplunger being shiftable from an extended position spaced from saidelectromagnet to a proximate position substantially tric power of afirst particular value to said coil to effect imate position; and meansfor supplying electric power to said coil of a secondparticular valuesubstantially less than said first value to retain said plunger in saidproximate position; said electric power of a first value comprising afirst sourcepro'viding a relatively high potential; saidvelectric powerof a second .value comprising a second source providing a relativelylower 'potential than said high potentiah'switching means forselectively connecting said first source of highpotential to said coilto shift said plunger from said extended position to saidproximat'eposition or for connecting said second source of lowerpotential to said 'coilto retain saidvplunger in said proximateposition; wherein said switching means comprisesa first relayselectively'energizable by the lower potential to introduce the higherpotential to the coil, a second .relay connected to the first relay andenergizable to introduce the lower potentialto thecoil, a first normallyopen switch .connected to the source of lower potential and operable tosimultaneously energize the-first and second relaysso that the. lowerpotential is introduced to the-second relayand the high potential isintroduced tothe coil,

and means for continuing current flow from the lower potential throughthe second and 'first'relays to the coil after the first switch isopened toreduce the power consumed and maintaining the plunger in saidproximate position. 3 I I 4. In apparatus for effecting operation of afluid actuated devicervalve jmeans operatively connected to a source offluid pressure and to the device, said'valve means including a valvemember shiftable between .a first position preventing flow of fluid fromthejsource to-the device and a second position permittingflow of fluidfrom the source to the device; anielectromagn'et .having a coil; aplunger connected to said valve member for shifting said'valve-member,from one of said positions to the other of said positions, said'plungerbeing shiftable from an extended position spaced'from'saidelectromagnet'to a proximate position substantially tial is introducedto the second relay and the high potential is introduced to theelectrically actuated means, and means for continuing current flow fromthe lower potential through the second and first'relays to theelectrically actuated means after the first switch is opened to reducethe power consumed and maintaining the valvemember in said secondposition.

3. ln apparatus for effecting-operation of a fluid actuated device:'valve means operativelyconnected to a source of fluid pressure and tothe device, said valve means'including a valve member shiftable betweena first position preventing flow of fluid from the source to the deviceand a second position permitting flow of fluid from the source tothedevice; an electromagnet having a coil; a plunger connected to saidvalve member for shifting said valve member'from one of said poshiftingof said plunger from extendedposition' to proximate position; and meansfor supplying electric power to said coil of a second particular valuesubstantially less thansaid first value tovretain said plunger in saidproximate position; wherein said'one of said positions is said firstposition and said other of said positions is said second position; saidelectric power of a first value comprisinga first source providing arelatively high potential; said-electric power of a second valuecompris-, ing a second source providing a relatively lower potentialthansaid high potential; switching means for selectively connecting saidfirst source of high potential to said coil to shift said plunger tosaidproximate position or for connecting said second source of low potentialto said coil to retainvsaid plungerin said proximate p0- sition'; saidswitching means comprising'a first relay selectively energizable by thelower potential tointroduce the higher potential to the coil, a secondrelay connected to said first relay and energizable to introduce thelower potential to the coil, a first normally open switch connected tothe source of lower potential and operable to simultaneously energizethe firstand second relays so that the lower potential is introduce tothe second relay'and the higher potential is introduced a source offluid pressure and to the device, said valve means including a valvemember shiftable between a first-position preventing'flow of fluid fromthe source cally actuated means after the first switch is opened -toreduce the power consumedandimaintain the valve member in said otherposition.

6. In apparatus as defined in claim 5; wherein said one of saidpositions is said first position and said other I of said positions issaid second position.

7. ln apparatus for effecting operatio'n of a fluid actuated device:valve means operatively connected to a source of fluid pressure'and tothe device, said valve to the device and a second position permittingflow of 15 fluid from the source to the device; an electrically actuatedmeans operatively connected to said valve member for shifting said valvemember from one of said positions to the other of said positions;

a first source providing a relatively high electric potential; asecondsource providing a relatively low electric potential;

a first relay selectively energizable by the lower potential tointroduce the higher potential to the electrically actuated means, asecond relay connected to the first relay and energizable to introducethe lower potential to the electrically actuated means, a first normallyopen switch connected to the source of lower potential and operable tosimultaneously energize the first and second relays so that the lowerpotential is introduced to the second relay and the high potential isintroduced to the electrically actuated means, and means for continuingcurrent flow from the lower potential through the second and firstrelays to the electrimeans includinga valve member shiftab le between afirst position preventing flow of fluid from the source to the deviceand a second position permitting flow of fluid from; the source-to thedevice; an electromagnet having a coil; a plunger connected to saidvalve member for shifting said valve member from one of said positionsto the other of said positions, said. plunger being shiftable from andextended position spaced from said electromagnet to a proximate positionsubstantially closer to said electromagnet; a first source providing arelatively high electric potential; a second source pro.- viding arelatively low electric potential; a first relay selectively energizableby the low potential to introduce the higher potential to the coil, asecond relay connected to the first relay and energizable tointroducethe lower potential to the coil, a firstnormally open switchconnected to the source of lower potential and operable tosimultaneously energize the first and second relays so that the lowerpotential is introduced to the second relay and the high potential isintroduced to the coil, and means for continuing current flow from thelower potential through the secondand' first relays to the coil afterthe first switch is opened to reduce the power consumed and maintainingthe plunger in said 7 proximate position. Y

1. In apparatus for effecting operation of a fluid actuated device:valve means operatively connectable to a source of fluid pressure and tothe device, said valve means including a valve member shiftable betweena first position preventing flow of fluid from tHe source to the deviceand a second position permitting flow of fluid from the source to thedevice; an electrically actuated means operatively connected to saidvalve member for shifting said valve member from one of said positionsto the other of said positions; means for supplying electric power of afirst particular value to said electrically actuated means to effectshifting of said valve member from said one position to said otherposition; and means for supplying electric power to said electricallyactuated means of a second particular value substantially less than saidfirst value to retain said valve means in said other position; saidelectric power of a first value comprising a first source providing arelatively high potential; said electric power of a second valuecomprising a second source providing a relatively lower potential thansaid high potential; switching means for selectively connecting saidfirst source of high potential to said electrically actuated means toshift said valve member to said other position or for connecting saidsecond source of lower potential to said electrically actuated means toretain said valve member in said other position; wherein said switchingmeans comprises a first relay selectively energizable by the lowerpotential to introduce the higher potential to the electrically actuatedmeans, a second relay connected to the first relay and energizable tointroduce the lower potential to the electrically actuated means, afirst normally open switch connected to the source of lower potentialand operable to simultaneously energize the first and second relays sothat the lower potential is introduced to the second relay and the highpotential is introduced to the electrically actuated means, and meansfor continuing current flow from the lower potential through the secondand first relays to the electrically actuated means after the firstswitch is opened to reduce the power consumed and maintain the valvemember in said other position.
 2. In apparatus for effecting operationof a fluid actuated device: valve means operatively connectable to asource of fluid pressure and to the device said valve means including avalve member shiftable between a first position preventing flow of fluidfrom the source to the device and a second position permitting flow offluid from the source to the device; an electrically actuated meansoperatively connected to said valve member for shifting said valvemember from one of said positions to the other of said positions; meansfor supplying electric power of a first particular value to saidelectrically actuated means to effect shifting of said valve member fromsaid one position to said other position; and means for supplyingelectric power to said electrically actuated means of a secondparticular value substantially less than said first value to retain saidvalve means in said other position; wherein said one of said positionsis said first position and said other of said positions is said secondposition; said electric power of a first value comprising a first sourceproviding a relatively high potential; said electric power of a secondvalue comprising a second source providing a relatively lower potentialthan said high potential; switching means for selectively connectingsaid first source of higher potential to said electrically actuatedmeans to shift said valve member to said second position or forconnecting said second source of lower potential to said electricallyactuated means to retain said valve member in said second position;wherein said switching means comprises a first relay selectivelyenergizable by the lower potential to introduce the higher potential tothe electrically actuated means, a second relay connected to the firstrelay and energizable to introduce the lower potential to theelectrically actuated means, a first normally open switch connected tothe source of lower potential and operable to simultaneously energizethe first and second relays so that the lower potentiAl is introduced tothe second relay and the high potential is introduced to theelectrically actuated means, and means for continuing current flow fromthe lower potential through the second and first relays to theelectrically actuated means after the first switch is opened to reducethe power consumed and maintaining the valve member in said secondposition.
 3. In apparatus for effecting operation of a fluid actuateddevice: valve means operatively connected to a source of fluid pressureand to the device, said valve means including a valve member shiftablebetween a first position preventing flow of fluid from the source to thedevice and a second position permitting flow of fluid from the source tothe device; an electromagnet having a coil; a plunger connected to saidvalve member for shifting said valve member from one of said positionsto the other of said positions, said plunger being shiftable from anextended position spaced from said electromagnet to a proximate positionsubstantially closer to said electromagnet; means for supplying electricpower of a first particular value to said coil to effect shifting ofsaid plunger from extended position to proximate position; and means forsupplying electric power to said coil of a second particular valuesubstantially less than said first value to retain said plunger in saidproximate position; said electric power of a first value comprising afirst source providing a relatively high potential; said electric powerof a second value comprising a second source providing a relativelylower potential than said high potential; switching means forselectively connecting said first source of high potential to said coilto shift said plunger from said extended position to said proximateposition or for connecting said second source of lower potential to saidcoil to retain said plunger in said proximate position; wherein saidswitching means comprises a first relay selectively energizable by thelower potential to introduce the higher potential to the coil, a secondrelay connected to the first relay and energizable to introduce thelower potential to the coil, a first normally open switch connected tothe source of lower potential and operable to simultaneously energizethe first and second relays so that the lower potential is introduced tothe second relay and the high potential is introduced to the coil, andmeans for continuing current flow from the lower potential through thesecond and first relays to the coil after the first switch is opened toreduce the power consumed and maintaining the plunger in said proximateposition.
 4. In apparatus for effecting operation of a fluid actuateddevice: valve means operatively connected to a source of fluid pressureand to the device, said valve means including a valve member shiftablebetween a first position preventing flow of fluid from the source to thedevice and a second position permitting flow of fluid from the source tothe device; an electromagnet having a coil; a plunger connected to saidvalve member for shifting said valve member from one of said positionsto the other of said positions, said plunger being shiftable from anextended position spaced from said electromagnet to a proximate positionsubstantially closer to said electromagnet; means for supplying electricpower of a first particular value to said coil to effect shifting ofsaid plunger from extended position to proximate position; and means forsupplying electric power to said coil of a second particular valuesubstantially less than said first value to retain said plunger in saidproximate position; wherein said one of said positions is said firstposition and said other of said positions is said second position; saidelectric power of a first value comprising a first source providing arelatively high potential; said electric power of a second valuecomprising a second source providing a relatively lower potential thansaid high potential; switching means for selectively connecting saidfirst source of high potential to said coil to shift said plunger tosaid proximate position or for connecting said second source of lowpotential to said coil to retain said plunger in said proximateposition; said switching means comprising a first relay selectivelyenergizable by the lower potential to introduce the higher potential tothe coil, a second relay connected to said first relay and energizableto introduce the lower potential to the coil, a first normally openswitch connected to the source of lower potential and operable tosimultaneously energize the first and second relays so that the lowerpotential is introduce to the second relay and the higher potential isintroduced to the coil, and means for continuing current flow from thelower potential through the second and first relays to the coil afterthe first switch is opened to reduce the power consumed and maintainingthe plunger in said proximate position.
 5. In an apparatus forcontrolling operation of a fluid actuated device: Valve means operableconnectable to a source of fluid pressure and to the device, said valvemeans including a valve member shiftable between a first positionpreventing flow of fluid from the source to the device and a secondposition permitting flow of fluid from the source to the device; anelectrically actuated means operatively connected to said valve memberfor shifting said valve member from one of said positions to the otherof said positions; a first source providing a relatively high electricpotential; a second source providing a relatively low electricpotential; a first relay selectively energizable by the lower potentialto introduce the higher potential to the electrically actuated means, asecond relay connected to the first relay and energizable to introducethe lower potential to the electrically actuated means, a first normallyopen switch connected to the source of lower potential and operable tosimultaneously energize the first and second relays so that the lowerpotential is introduced to the second relay and the high potential isintroduced to the electrically actuated means, and means for continuingcurrent flow from the lower potential through the second and firstrelays to the electrically actuated means after the first switch isopened to reduce the power consumed and maintain the valve member insaid other position.
 6. In apparatus as defined in claim 5; wherein saidone of said positions is said first position and said other of saidpositions is said second position.
 7. In apparatus for effectingoperation of a fluid actuated device: valve means operatively connectedto a source of fluid pressure and to the device, said valve meansincluding a valve member shiftable between a first position preventingflow of fluid from the source to the device and a second positionpermitting flow of fluid from the source to the device; an electromagnethaving a coil; a plunger connected to said valve member for shiftingsaid valve member from one of said positions to the other of saidpositions, said plunger being shiftable from and extended positionspaced from said electromagnet to a proximate position substantiallycloser to said electromagnet; a first source providing a relatively highelectric potential; a second source providing a relatively low electricpotential; a first relay selectively energizable by the low potential tointroduce the higher potential to the coil, a second relay connected tothe first relay and energizable to introduce the lower potential to thecoil, a first normally open switch connected to the source of lowerpotential and operable to simultaneously energize the first and secondrelays so that the lower potential is introduced to the second relay andthe high potential is introduced to the coil, and means for continuingcurrent flow from the lower potential through the second and firstrelays to the coil after the first switch is opened to reduce the powerconsumed and maintaining the plunger in said proximate position.